Featherbed frame crack issues

It might be worth bearing in mind, with regard to this cracking issue (good pun there) that the material used for making Manx frames differes from that generally used on the Inter version. Plus cracking and bending frames has caught out the Norton Factory on a regular basis. The Featherbed frames cracked under the headstock and around the downtube engine mounts. The Mercury frames seemed to be made of plasticine and easily folded or twisted. The early Commando also had its share of grief that only ended after a redesign around the headstock. Even the new 961 has not escaped with a number of early frames being rejected due to rust around the weldings.

This, I'm sure, came up a long time ago, probably in Rodholder, with, I think, John Hudson's opinion on the matter. I seem to recall that Rex Mac Candless, who designed the frame, warned Norton that the frame would crack precisely there, and Norton didn't take any notice.

They all do that, sir. I have two featherbed frames, and they both did. After an accident in 93, before trhe Czech rally, I had to get the frame straightened on my atlas, and they welded it up. It cracked again. Three years ago, the frame being badly damaged on the lower loop, where the main stand hits it when springing up, I took it to a very good frame repairer in Bordeaux, and he rewelded it. It's not cracked again... yet. My other frame, on my special, is cracked too, has been for ages, but that didn't stop me going to Austria several times, England and Germany last year, and various other rallies, it doesn't seemto get any worse. Anyway, I'm definitely not going to worry about it.

The problem with welding up cracks is the method used to do it. The worst being arc welding which can destroy the property of the metal being fixed. You then end up with what is known as 'brittle weld failure' where the metal each side of the welded section suffers metalurgical changes and becomes incredibly fragile. Extremes of weather and viabration can trigger such joints into failing. MiG or TiG should be safer but this is what John Morgan had down and his frame fix still failed.

According to Dave Degans of Dresda Autos fame. The safest method is to braze any frame cracks or joints that need repairs. Frames constructed of 531 were bronze brazed,

The Featherbed frames were welded mostly where the metal was thickest. ie around the head stock. How the cross tubes were welded in without causing problems I do not know. But the rear silencer/footrest hangers were well known for cracking at the frame joint.

Some Inter and also some early 88 bikes had proper Manx frames constructed from 531. Most, however, had frames constructed from mild steel. grade A for the Inter and grade B for the standard roadgoing machines.

Stop bragging about your age or I might have to send an article, about Zimmers Frames, in to Roadholder.

My first cracking experience (another bad pun) happened in 1982 when the welded-in cross-tube, above the swinging arm, on my 1967 Atlas decided to impersonate a jigsaw. Not that old for a frame but it had spent its first 4 years as a proddie racer and then clocked up 70,000 road miles. None of the local bike shops would touch it when I tried to get the cracks welded-up as they all believed the tubing to be 531. In the end, I hacked a length of angled steel off an old road sign and arc welded it to the cross-tube myself. It was still in place 20 years later.

Stop bragging about your age or I might have to send an article, about Zimmers Frames, in to Roadholder.

My first cracking experience (another bad pun) happened in 1982 when the welded-in cross-tube, above the swinging arm, on my 1967 Atlas decided to impersonate a jigsaw. Not that old for a frame but it had spent its first 4 years as a proddie racer and then clocked up 70,000 road miles. None of the local bike shops would touch it when I tried to get the cracks welded-up as they all believed the tubing to be 531. In the end, I hacked a length of angled steel off an old road sign and arc welded it to the cross-tube myself. It was still in place 20 years later.

Hello phil Quick folding featherbed frames and Zimmer frames for sale on ebay! and by 60 odd years were all cracking up by then anyway if you need a frame welding Mig or Tig is the best way too go, yours Anna J

At last! Someone else who has used a bit of road sign to repair a bike. I have used arc weld to repair the ears which hold the passenger footrests and silencers. Not the neatest job but it worked fine. I once identified a stolen bike by standing up in court and describing a welding repair I did on it. Again, not a beautiful weld but myall too honest description of itconvinced the sheriff. The T Leaf was convicted and the bike returned to its rightful owner.